The friendship between Michael J. Fox and Christopher Lloyd took some time to build.

Speaking with Variety at the Sundance Film Festival, Fox looked back on working with Lloyd in the “Back to the Future” trilogy and how they got to know each other over the films.

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“Chris is a great guy. He’s very enigmatic,” he said. “It took me a few films to get to know him. On ‘Back to the Future Part III’ we connected in a way we hadn’t on the other films. I came to see how much he loved acting. I never got that before.”

Fox continued, “To sit down and talk about acting, and talk about Shakespeare and King Lear… This guy can play King Lear! People don’t expect that of him. He’s full of surprises.”

The Canadian actor went on to describe just how talented Lloyd is as an actor.

“He can tell a movie’s worth of story in two seconds and you get it,” he said. “Us regular actors have to lay out hours and hours to get the information out. Chris is brilliant at it. His love of film and his love of being an actor… He’s not just a crazy guy, he’s an artist.”

READ MORE: Michael J. Fox Says He Was In ‘Denial’ For 7 Years After Parkinson’s Diagnosis: ‘I Only Knew It Would Get Worse’

Last October, the duo reunited at New York Comic-Con, where Fox praised Lloyd for sticking by him through his Parkinson’s diagnosis in 1991.

“Parkinson’s is the gift that keeps on taking. But it’s a gift, and I wouldn’t change it for anything,” Fox said at the time. “People like Chris have been there a lot for me, and so many of you have. It’s not about what I have, it’s about what I’ve been given, the voice to get this done, and help people out.”

Meanwhile, Fox is currently at Sundance as the subject of the new documentary from “An Inconvenient Truth” director Davis Guggenheim, “Still: A Michael J. Fox Movie”.